Polyurethane dispersions for use in personal care products

ABSTRACT

The invention relates to an aqueous polyurethane dispersion suitable for use in personal care products, the dispersed polyurethane comprising the reaction products of:
         A) a prepolymer according to the formula:       

     
       
         
         
             
             
         
       
         
         
           
             
               
                 wherein 
                 R 1  represents a bivalent radical of a dihydroxyl functional compound, 
                 R 2  represents a hydrocarbon radical of an aliphatic or cycloaliphatic polyisocyanate, 
                 R 3  represents a radical of a low molecular weight diol, optionally substituted with ionic groups, 
                 n is from 0 to 5, and 
                 m is &gt;1; 
               
             
             B) at least one chain extender according to the formula:
 
H 2 N—R 4 —NH 2  
           wherein R 4  represents an alkylene or alkylene oxide radical not substituted with ionic or potentially ionic groups; and   
         
             C) at least one chain extender according to the formula:
 
H 2 N—R 5 —NH 2  
           wherein R 5  represents an alkylene radical substituted with ionic or potentially ionic groups.

BACKGROUND OF THE INVENTION

The invention relates to aqueous polyurethane dispersions, to a processfor preparing them and to their use in cosmetic applications such ashair fixatives.

Polyurethane dispersions have recently been incorporated into cosmeticproducts, such as hair fixatives, suntan lotions, etc., offering severaladvantages over conventional technologies such as acrylics and acrylamide copolymers, polyvinyl pyrrolidone, and PVP/VA copolymers. Suchadvantages include water compatibility, ease of formulating low VOCsprays, water resistance and excellent film forming ability.Specifically in hair care products, polyurethane dispersions providegreat setting effect without sticky feel, excellent style retentionowing to the polymer's elastic memory, natural look and feel. All theseattributes are highly valuable to the consumer. Commercial polyurethanedispersions designed as hair fixatives and hair styling polymersgenerally exhibit good high humidity curl retention, style retention,good feel and shine. However, their lack of adhesion to hair isdemonstrated by extensive flakiness on hair after combing. This createsa significant aesthetic problem for consumers.

The challenge of designing a hair fixative polymer consists of achievinga balance between often conflicting requirements: the polymer should behydrophobic enough to provide curl retention even under humidconditions, while it should remain sufficiently hydrophilic in order tobe removable from hair by washing with water. Also, the polymer has toposses an optimum combination of glass transition temperature,flexibility and molecular weight to provide setting strength,elasticity, adhesion to hair and soft feel.

U.S. Pat. No. 5,626,840 discloses hair fixatives based on polyurethanedispersions that are prepared utilizing 2,2-hydroxymethyl-substitutedcarboxylic acid. It illustrates how to achieve good humidity resistanceand spray characteristics using water soluble or dispersablepolyurethanes. The examples demonstrate the efficacy of the polymer onlyin aerosol spray formulations containing alcohol. This is detrimentalfor both the environment and the health of the hair. Finally, theinvention utilizes a range of dimethylol propionic acid (DMPA) of0.35-2.25 meq of COOH per gram of polyurethane in the polyurethanedispersion that must be observed in order for the dispersion to beeffective.

However, the disclosure does not teach how to avoid the common problemof the polymer's flakiness on hair by achieving good adhesion to hair.Moreover, it does not teach how to attain style retention, e.g. elasticbehavior of the polymer. Finally, a lower amount of acid shouldpreferably be used, while still achieving curl retention andwashability, as the acid tends to accelerate the breakdown of thepolymer.

U.S. Pat. No. 6,613,314 discloses reshapeable hair compositions thatutilize polyurethane dispersions. During preparation of thepolyurethane, an isocyanate-functional prepolymer is formed. Theprepolymer incorporates at least one polyactive hydrogen compound thatis soluble in the medium of dispersion. Preferably, sulfonated compoundsare utilized. The sulfonic group is incorporated into the prepolymer,rather than via the urea segment.

U.S. Pat. No. 6,106,813 discloses polyester polyurethanes that aresuitable in cosmetic applications. It discloses a new family ofpolyester polyurethanes that possess not only good film-formingproperties, but also impart great rigidity and excellent resistance toremoval by water and detergents. With regard to the hair styling/hairfixative applications, the examples in the patent demonstrate the use ofthe invention only in hair style shaping lotions, claiming good shaperetention.

However, the reference does not mention adhesion to hair or how toachieve excellent humidity resistance with good removability by water.It also does not mention important attributes of hair styling/hairfixative polymers, such as natural feel and luster on hair.

Thus, the purpose of present invention was to provide a polymercomposition which would improve adhesion to hair and also demonstrateexcellent curl and style retention, natural feel and look.

The present invention provides a composition that demonstrates excellentadhesion to hair. In comparison to commercially available hair fixativepolyurethane dispersions, the composition of the present inventionimpart significantly less or no flaking at all. In addition, it providesimproved humidity retention, higher luster and natural feel incomparison to the above-mentioned polyurethane dispersions.

SUMMARY OF THE INVENTION

The present invention relates to an aqueous polyurethane dispersionsuitable for use in personal care products, the dispersed polyurethanecomprising the reaction products of:

-   -   A) a prepolymer according to the formula:

-   -   wherein        -   R₁ represents a bivalent radical of a dihydroxyl functional            compound,        -   R₂ represents a hydrocarbon radical of an aliphatic or            cycloaliphatic polyisocyanate,        -   R₃ represents a radical of a low molecular weight diol,            optionally substituted with ionic groups,        -   n is from 0 to 5, and        -   m is >1;    -   B) at least one chain extender according to the formula:        H₂N —R₄—NH₂        -   wherein R₄ represents an alkylene or alkylene oxide radical            not substituted with ionic or potentially ionic groups; and    -   C) at least one chain extender according to the formula:        H₂N—R₅—NH₂        -   wherein R₅ represents an alkylene radical substituted with            ionic or potentially ionic groups.

The present invention also relates to a process for preparing a hairfixative comprising:

-   -   A) preparing an aqueous polyurethane dispersion by        -   1) forming a isocyanate-functional prepolymer by reacting            -   1a) a polyol,            -   1b) an aliphatic or cycloaliphatic polyisocyanate, and            -   1c) a low molecular weight diol optionally substituted                with ionic groups;        -   2) chain-extending the prepolymer with            -   2a) at least one chain extender according to the                formula:                H₂N—R₄—NH₂            -   wherein R₄ represents an alkylene or alkylene oxide                radical not substituted with ionic or potentially ionic                groups, and 2b) at least one chain extender according to                the formula:                H₂N—R₅—NH₂            -   wherein R₅ represents an alkylene radical substituted                with ionic or potentially ionic groups,        -   in the presence of an organic solvent to form a            polyurethane;        -   3) dispersing the polyurethane in water; and        -   4) removing the organic solvent, resulting in an aqueous            polyurethane dispersion; and    -   mixing the polyurethane dispersion with water or ethanol.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Suitable dihydroxyl compounds for providing the bivalent radical R₁ arethose having two hydroxy groups and having number average molecularweights of from about 700 to about 16,000, and preferably from about 750to about 5000. Examples of the high molecular weight compounds arepolyester polyols, polyether polyols, polyhydroxy polycarbonates,polyhydroxy polyacetals, polyhydroxy polyacrylates, polyhydroxypolyester amides, polyhydroxy polyalkadienes and polyhydroxypolythioethers. The polyester polyols, polyether polyols and polyhydroxypolycarbonates are preferred. Mixtures of various such compounds arealso within the scope of the present invention.

The polyester diol(s) may be prepared in known manner from aliphatic,cycloaliphatic or aromatic dicarboxylic or polycarboxylic acids oranhydrides thereof (for example, succinic, glutaric, adipic, pimelic,suberic, azelaic, sebacic, nonanedicarboxylic, decanedicarboxylic,terephthalic, isophthalic, o-phthalic, tetrahydrophthalic,hexahydrophthalic or trimellitic acid) as well as acid anhydrides (suchas o-phthalic, trimellitic or succinic acid anhydride or a mixturethereof) and dihydric alcohols such as, for example, ethanediol,diethylene, triethylene, tetraethylene glycol, 1,2-propanediol,dipropylene, tripropylene, tetrapropylene glycol, 1,3-propanediol,1,4-butanediol, 1,3-butanediol, 2,3-butanediol, 1,5-pentanediol,1,6-hexanediol, 2,2-dimethyl-1,3-propanediol, 1,4-dihydroxycyclohexane,1,4-dimethylolcyclohexane, 1,8-octanediol, 1,10-decanediol,1,12-dodecanediol or mixtures thereof. Cycloaliphatic and/or aromaticdihydroxyl compounds are, of course, also suitable as the dihydricalcohol(s) for the preparation of the polyester polyol(s). Thecorresponding polycarboxylic acid anhydrides or correspondingpolycarboxylic acid esters of low alcohols, or mixtures thereof, mayalso be used in place of the free polycarboxylic acid for thepreparation of the polyesters.

The polyester diols may naturally also be homopolymers or copolymers oflactones, which are preferably obtained by addition reactions oflactones or lactone mixtures, such as butyrolactone, ε-caprolactoneand/or methyl-ε-caprolactone with the suitable difunctional startermolecules such as, for example, the low molecular weight dilyhydricalcohols mentioned above. The corresponding polymers of ε-caprolactoneare preferred.

Polycarbonates containing hydroxy groups include those known per se suchas the products obtained from the reaction of diols such aspropanediol-(1,3), butanediol-(1,4) and/or hexanediol-(1,6), diethyleneglycol, triethylene glycol or tetraethylene glycol withdiarylcarbonates, e.g. diphenylcarbonate or phosgene.

Suitable polyether polyols are obtained in known manner by the reactionof starting compounds which contain reactive hydrogen atoms withalkylene oxides such as ethylene oxide; propylene oxide; butylene oxide;styrene oxide; tetrahydrofuran or epichlorohydrin or with mixtures ofthese alkylene oxides. It is preferred that the polyethers do notcontain more than about 10% by weight of ethylene oxide units. Mostpreferably, polyethers obtained without the addition of ethylene oxideare used.

Suitable starting compounds containing reactive hydrogen atoms include,e.g. water and the dihydric alcohols set forth for preparing thepolyester polyols.

Polyethers modified by vinyl polymers are also suitable according to theinvention. Products of this kind may be obtained by polymerizing, e.g.styrene and acrylonitrile in the presence of polyethers (U.S. Pat. Nos.3,383,351; 3,304,273; 3,523,095; 3,110,695 and German Pat. No.1,152,536).

Among the polythioethers which should be particularly mentioned are thecondensation products obtained from thiodiglycol on its own and/or withother glycols, dicarboxylic acids, formaldehyde, aminocarboxylic acidsor amino alcohols. The products obtained are either polythio-mixedethers, polythioether esters or polythioether ester amides, depending onthe co-components.

Suitable polyacetals include the compounds which can be prepared fromaldehydes, e.g. formaldehyde, and glycols such as diethylene glycol,triethylene glycol, ethoxylated 4,4′-dihydroxy-diphenyldimethylmethane,and hexanediol-(1,6). Polyacetals suitable for the purpose of theinvention may also be prepared by the polymerization of cyclic acetals.

Suitable polyhydroxy polyester amides and polyamines are, for example,the predominantly linear condensates obtained from polybasic saturatedand unsaturated carboxylic acids or their anhydrides and polyvalentsaturated or unsaturated aminoalcohols, diamines, polyamines andmixtures thereof.

Suitable monomers for producing hydroxyfunctional polyacrylates includeacrylic acid, methacrylic acid, crotonic acid, maleic anhydride,2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropylacrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl acrylate,3-hydroxypropyl methacrylate, glycidyl acrylate, glycidyl methacrylate,2-isocyanatoethyl acrylate and 2-isocyanatoethyl methacrylate.

Suitable polyalkadienes include polybutadienes and polyisoprenes, suchas POLY bd resin from Elf Atochem North America, Philadelphia, Pa. Alsoincluded are hydrogenated polyisoprene and hydrogenated polybutadiene.Examples of those include KRATON L-2203 from Shell chemical, Houston,Tex., and POLYTAIL resins from Mitsubishi Chemical, Tokyo, Japan.

Mixtures of the above-described dihydroxy compounds can also be used.

Suitable polyisocyanates for providing the hydrocarbon radical R₂include organic diisocyanates having a molecular weight of from about112 to 1,000, and preferably from about 140 to 400. Preferreddiisocyanates are those represented by the general formula R₂(NCO)₂indicated above in which R₂ represents a divalent aliphatic hydrocarbongroup having from 4 to 18 carbon atoms, a divalent cycloaliphatichydrocarbon group having from 5 to 15 carbon atoms, a divalentaraliphatic hydrocarbon group having from 7 to 15 carbon atoms or adivalent aromatic hydrocarbon group having 6-15 carbon atoms. Examplesof the organic diisocyanates which are suitable include tetramethylenediisocyanate, 1,6-hexamethylene diisocyanate, dodecamethylenediisocyanate, cyclohexane-1,3- and -1,4-diisocyanate,1-isocyanato-3-isocyanatomethyl-3,5,5-trimethylcyclohexane (isophoronediisocyanate or IPDI), bis-(4-isocyanatocyclohexyl)-methane, 1,3- and1,4-bis(isocyanatomethyl)-cyclohexane,bis-(4-isocyanato-3-methyl-cyclohexyl)-methane, isomers of toluenediisocyanate (TDI) such as 2,4-diisocyanatotoluene,2,6-diisocyanatotoluene, mixtures of these isomers, hydrogenated TDI,4,4′-diisocyanato diphenyl methane and its isomeric mixtures with 2,4′-and optionally 2,2′-diisocyanato diphenylmethane, and 1,5-diisocyanatonaphthalene. Mixtures of diisocyanates can, of course, be used.Preferred diisocyanates are aliphatic and cycloaliphatic diisocyanates.Particularly preferred are 1,6-hexamethylene diisocyanate and isophoronediisocyanate.

The low molecular weight diols usually result in a stiffening of thepolymer chain, and are optionally used. By “low molecular weight diols”it is meant diols having a molecular weight from about 62 to 700,preferably 62 to 200. They may contain aliphatic, alicyclic or aromaticgroups. Preferred compounds contain only aliphatic groups. The lowmolecular weight diols having up to about 20 carbon atoms per moleculeinclude ethylene glycol, diethylene glycol, propane 1,2-diol, propane1,3-diol, butane 1,4-diol, butylene 1,3-glycol, neopentyl glycol, butylethyl propane diol, cyclohexane diol, 1,4-cyclohexane dimethanol, hexane1,6-diol, bisphenol A (2,2-bis(4-hydroxyphenyl)propane), hydrogenatedbisphenol A (2,2-bis(4-hydroxycyclohexyl)propane), and mixtures thereof.

Optionally, the low molecular weight diols may contain ionic orpotentially ionic groups. Suitable lower molecular weight diolscontaining ionic or potentially ionic groups are those disclosed in U.S.Pat. No. 3,412,054. Preferred compounds include dimethylol butanoic acid(DMBA), dimethylol propionic acid (DMBA) and carboxyl-containingcaprolactone polyester diol. If lower molecular weight diols containingionic or potentially ionic groups are used, they are used in an amountsuch that <0.30 meq of COOH per gram of polyurethane in the polyurethanedispersion are present. Preferably, the low molecular weight diolscontaining ionic or potentially ionic groups are not used.

The prepolymer is chain extended using two classes of chain extenders.First, compounds having the formula:H₂N—R₄—NH₂wherein R₄ represents an alkylene or alkylene oxide radical notsubstituted with ionic or potentially ionic groups. Alkylene diaminesinclude hydrazine, ethylenediamine, propylenediamine,1,4-butylenediamine and piperazine. The alkylene oxide diamines include3-{2-[2-(3-aminopropoxy)ethoxy]ethoxy}propylamine (also known asdipropylamine diethyleneglycol or DPA-DEG available from Tomah Products,Milton, Wis.), 2-methyl-1,5-pentanediamine (Dytec A from DuPont), hexanediamine, isophorone diamine, and 4,4-methylenedi-(cyclohexylamine), andthe DPA-series ether amines available from Tomah Products, Milton, Wis.,including dipropylamine propyleneglycol, dipropylaminedipropyleneglycol, dipropylamine tripropyleneglycol, dipropylaminepoly(propylene glycol), dipropylamine ethyleneglycol, dipropylaminepoly(ethylene glycol), dipropylamine 1,3-propane diol, dipropylamine2-methyl-1,3-propane diol, dipropylamine 1,4-butane diol, dipropylamine1,3-butane diol, dipropylamine 1,6-hexane diol and dipropylaminecyclohexane-1,4-dimethanol. Mixtures of the listed diamines may also beused.

The second class of chain extenders are compounds having the formula:H₂N—R₅—NH₂wherein R₅ represents an alkylene radical substituted with ionic orpotentially ionic groups. Such compounds have an ionic or potentiallyionic group and two groups that are reactive with isocyanate groups.Such compounds contain two isocyanate-reactive groups and an ionic groupor group capable of forming an ionic group. The ionic group orpotentially ionic group can be selected from the group consisting ofternary or quaternary ammonium groups, groups convertible into such agroup, a carboxyl group, a carboxylate group, a sulfonic acid group anda sulfonate group. The at least partial conversion of the groupsconvertible into salt groups of the type mentioned may take place beforeor during the mixing with water. Specific compounds includediaminosulfonates, such as for example the sodium salt ofN-(2-aminoethyl)-2-aminoethane sulfonic acid (AAS) or the sodium salt ofN-(2-aminoethyl)-2-aminopropionic acid.

The polyurethane according to the invention may also include compoundswhich are situated in each case at the chain ends and terminate saidchains (chain terminators). These chain terminators can be derived fromcompounds having the formula:

wherein R₆ is an H atom or alkylene radical optionally having a hydroxylend and R₇ is alkylene radical optionally having a hydroxyl end.Suitable compounds include compounds such as monoamines, particularlymonosecondary amines, or monoalcohols. Examples include: methylamine,ethylamine, propylamine, butylamine, octylamine, laurylamine,stearylamine, isononyloxy-propylamine, dimethylamine, diethylamine,dipropylamine, dibutylamine, N-methylaminopropylamine,diethyl(methyl)aminopropylamine, morpholine, piperidine, diethanolamineand suitable substituted derivatives thereof, amide amines of diprimaryamines and monocarboxylic acids, monoketimes of diprimary amines,primary/tertiary amines such as N,N-dimethylamino-propylamine and thelike. Also suitable are chain terminating alcohols such as, C₁-C₁₀ orhigher alcohols including, methanol, butanol, hexanol, 2-ethylhexylalcohol, isodecyl alcohol, and the like and even mixtures thereof, aswell as amino-alcohols such as aminomethylpropanol (AMP).

In one embodiment of the invention, diethylene glycol is incorporatedinto the polyurethane dispersion either as the low molecular weightdiol, or as part of the non-ionic chain extender through the use ofdipropylamine-diethyleneglycol. If the diethylene glycol is used as thelow molecular weight diol, then preferably the DPA-DEG is not used asthe non-ionic chain extender. Likewise, if the DPA-DEG is used as thenon-ionic chain extender, then diethylene glycol is preferably not usedas the low molecular weight diol. The use of the diethylene glycol orDPA-DEG is especially desirable when the polyurethane dispersion isincorporated into a hair fixative, as the diethylene glycolsignificantly increases the adhesion to hair.

The present invention also relates to a process for the production of apolyurethane dispersion suitable for use in personal care products,comprising a) reacting in a first step at least the dihydroxyl compoundsand the diisocyanate to form the prepolymer A), then b) dissolving in asecond step the prepolymer in an organic solvent and c) reacting in athird step the isocyanate-containing prepolymer solution with the twoclasses of chain extenders and optionally, the chain terminator, d)forming, in a fourth step, the dispersion by addition of water, and e)removing in a fifth step the organic solvent.

Free sulfonic acid groups incorporated are neutralized between the thirdand fourth step. Suitable neutralizing agents include are the primary,secondary or tertiary amines. Of these the trialkyl-substituted tertiaryamines are preferred. Examples of these amines are trimethyl amine,triethyl amine, triisopropyl amine, tributyl amine,N,N-dimethyl-cyclohexyl amine, N,N-dimethylstearyl amine,N,N-dimethylaniline, N-methylmorpholine, N-ethylmorpholine,N-methylpiperazine, N-methylpyrrolidine, N-methylpiperidine,N,N-dimethyl-ethanol amine, N,N-diethyl-ethanol amine, triethanolamine,N-methyldiethanol amine, dimethylaminopropanol, 2-methoxyethyldimethylamine, N-hydroxyethylpiperazine, 2-(2-dimethylaminoethoxy)-ethanol and5-diethylamino-2-pentanone. The most preferred tertiary amines are thosewhich do not contain active hydrogen(s) as determined by theZerewitinoff test since they are capable of reacting with the isocyanategroups of the prepolymers which can cause gelation, the formation ofinsoluble particles or chain termination.

The polyurethane dispersions according to the invention can be producedby the so-called acetone process. In the acetone process the synthesisof the aqueous preparations of polyurethane on which the dispersionsaccording to the invention are based is performed in a multistageprocess.

In a first stage a prepolymer containing isocyanate groups issynthesized from the dihydroxyl compound, the diisocyanate and the lowmolecular weight diol. The amounts of the individual components arecalculated in such a way that the isocyanate content of the prepolymersis between 1.4 and 5.0 wt. %, preferably between 2.0 and 4.5 wt. %, andparticularly preferably between 2.6 and 4.0 wt. %. The low molecularweight diol is present in an amount from 0 to 80 eq. % based on theamount of NCO equivalents, preferably from 0 to 10 eq. %.

The resulting prepolymer has a structure of:

-   -   wherein    -   R₁ represents a bivalent radical of a dihydroxyl functional        compound,    -   R₂ represents a hydrocarbon radical of an aliphatic or        cycloaliphatic polyisocyanate,    -   R₃ represents a radical of a low molecular weight diol,        optionally substituted with ionic groups,    -   n is <5, and    -   m is >1.

Preferably, n is from 1 to 3, and m is from 1 to 5.

In a second stage the prepolymer produced in stage 1 is dissolved in anorganic, at least partially water-miscible, solvent containing noisocyanate-reactive groups. The preferred solvent is acetone. Othersolvents, such as, for example, 2-butanone, tetrahydrofuran or dioxan ormixtures of these solvents can also be used, however. The quantities ofsolvent to be used must be calculated in such a way that a solidscontent of 25 to 60 wt. %, preferably 30 to 50 wt. %, particularlypreferably 35 to 45 wt. %, is obtained.

In a third stage the isocyanate-containing prepolymer solution isreacted with mixtures of the amino-functional chain extenders and,optionally, chain terminator, to form the high-molecular weightpolyurethane. Sufficient amounts of the chain extenders and chainterminator are used such that the calculated number-average molecularweight (Mn) of the resulting polyurethane is between 10,000 and 100,000daltons, preferably between 10,000 and 50,000 daltons. The non-ionicchain extender is present in an amount from 15 to 90 eq. %, preferably35.0 to 55 eq. %, based on the residual amount of NCO equivalentspresent in the prepolymer. The ionic chain extender is present in anamount from 10 to 50 eq. %, preferably from 25 to 35 eq. %, based on theresidual amount of NCO equivalents present in the prepolymer. The chainterminator is present in an amount from 0 to 35 eq. %, preferably from20 to 30 eq. %, based on the residual amount of NCO equivalents presentin the prepolymer.

In a fourth stage the high-molecular weight polyurethane is dispersed inthe form of a fine-particle dispersion by addition of water to thesolution or solution to the water.

In a fifth stage the organic solvent is partially or wholly removed bydistillation, optionally under reduced pressure. The amount of water instage four is calculated in such a way that the aqueous polyurethanedispersions according to the invention display a solids content of 20 to60 wt. %, preferably 28 to 42 wt. %.

The polyurethane dispersions of the present invention are suitable foruse in personal care products. Preferably, they are used in non-aerosolhair fixatives. Such hair fixatives are easily prepared by the additionof water or ethanol to the dispersion. Likewise, the dispersions may beused in the preparation of other personal care products such as suntanlotions, skin care products, lipstick, mascara and deodorants, by theaddition of components well known to those of ordinary skill in the art.

EXAMPLES

Non-aerosol hair fixative formulations were prepared utilizing deionizedwater and the polyurethane dispersions according to the invention. Theformulations were 4 parts polyurethane dispersion active resin solids bythe mixing of 10 parts polyurethane dispersion and 90 parts water. Thenon-aerosol spray formulations (20 ml) containing 3% active resin solidswere prepared as following: ((3/% solids PUD)×20 ml)/100=X g of PUDdissolved in (20-X) g of water.

Products Used in the Examples:

Desmophen® PE-170HN: polyesterdiol (M/wt. 1700, OH No. 66; adipic acidhexanediol neopentyl glycol ester, Bayer MateriaiScience LLC,Pittsburgh, Pa.)

Desmodur® H (1,6-hexamethylene diisocyanate, Bayer MaterialScience LLC,Pittsburgh, Pa.)

DPA-DEG (dipropylamine-diethyleneglycol, Tomah Products, Milton, Wis.)

Kathon® LX (biocide, Rohm & Haas, Philadelphia, Pa.)

Microcare® MTG (biocide, Thor Specialties (UK) Ltd., Cheshire, UK)

Example 1 Composition According to the Invention

32.08 g of Desmophen® PE-170HN, polyesterdiol (M/wt. 1700, OH No. 66;adipic acid hexanediol neopentyl glycol ester) and 0.19 g of neopentylglycol were reacted with 5.71 g of Desmodur® H (1,6-hexamethylenediisocyanate). When the reaction reached theoretical NCO %, theresulting prepolymer was cooled to 60° C. and dissolved in 60 g ofacetone. After mixing for 30 minutes, a solution of 0.66 g ofdipropylamine-diethyleneglycol (DPA-DEG from Tomah Products), 1.70 g ofAAS (N-(2-aminoethyl)-2-aminoethane sulfonic acid) sodium salt, 0.16 gof ethylenediamine and 0.61 g of diethanolamine (DEOA) in 8.53 gdistilled water was added dropwise. After mixing for 20 minutes, 58.14 gof distilled water at room temperature were added into reactor and theacetone was subsequently distilled off under reduced pressure. 0.52 g ofbiocide, Kathon® LX was added into the final product under agitation.

Example 2 Composition According to the Invention

31.95 g of Desmophen® PE-170HN, polyesterdiol (M/wt. 1700, OH No. 66;adipic acid hexanediol neopentyl glycol ester) and 0.24 g of dimethylolbutanoic acid (DMBA) were reacted with 5.69 g of Desmodur® H(1,6-hexamethylene diisocyanate). When the reaction reached theoreticalNCO %, the resulting prepolymer was cooled to 60° C. and dissolved in 60g of acetone. After mixing for 20 minutes, 0.17 g of AMP-95 (95% aq.solution of 2-amino-2-methyl-1-propanol) was added to the mixture toneutralize the acid. A solution of 1.31 g ofdipropylamine-diethyleneglycol (DPA-DEG from Tomah Products), 1.05 g ofAAS sodium (N-(2-aminoethyl)-2-aminoethane sulfonic acid) salt and 0.93g of diethanolamine (DEOA) in 8.53 g distilled water was added dropwise.After mixing for 20 minutes, 58.14 g of distilled water at roomtemperature were added into reactor and the acetone was subsequentlydistilled off under reduced pressure. 0.52 g of biocide, Microcare® MTGwas added into the final product under agitation.

Example 3 Comparative Example

32.22 g of Desmophen® PE-170HN, polyesterdiol (M/wt. 1700, OH No. 66;adipic acid hexanediol neopentyl glycol ester) were reacted with 5.74 gof Desmodur® H (1,6-hexamethylene diisocyanate). When the reactionreached theoretical NCO %, the resulting prepolymer was cooled to 60° C.and dissolved in 60 g of acetone. After mixing for 30 minutes, asolution of 1.52 g of AAS (N-(2-aminoethyl)-2-aminoethane sulfonic acid)sodium salt and 0.33 g of ethylenediamine in 8.53 g distilled water wasadded dropwise. After mixing for 20 minutes, 60.22 g of distilled waterat room temperature were added into reactor and the acetone wassubsequently distilled off reduced pressure. 0.52 g of biocide, Kathon®LX was added into the final product.

Example 4 Composition According to the Invention

30.70 g of Desmophen® PE-170HN, polyesterdiol (M/wt. 1700, OH No. 66;adipic acid hexanediol neopentyl glycol ester) and 0.23 g of neopentylglycol were reacted with 5.45 g of Desmodur® H (1,6-hexamethylenediisocyanate). When the reaction reached theoretical NCO %, 0.25 g ofdiethylene glycol was added into the reaction mixture: reactionproceeded for 1 hour at 90 C. The resulting prepolymer was cooled to 60°C. and dissolved in 60 g of acetone. After mixing for 30 minutes, asolution, 1.62 g of AAS (N-(2-aminoethyl)-2-aminoethane sulfonic acid)sodium salt, 0.11 g of ethylenediamine and 0.79 g of diethanolamine(DEOA) in 8.5 g distilled water was added dropwise. After mixing for 20minutes, 60.36 g of distilled water at room temperature were added intoreactor and the acetone was subsequently distilled off under reducedpressure. 0.5 g of biocide, Kathon LX, 1.5% solids solution, was addedinto the final product under agitation.

Curl retention testing was performed in accordance with the test methodsdetailed in U.S. Pat. No. 5,626,840. Spray bottles with fine mist wereused for application. The sample hair used was Yaki brown hair, 8 in.,color 4. The Curl Retention test was performed as follows. The hair iscut into swatches of ˜2 g. each and, bound together at one end. Eachswatch is washed in 10% solution of clarifying shampoo for 30 secondsand rinsed in warm tap water. The hair is cut into 6 in. lengths fromsecured end. The hair is wet again and then combed, and the excess wateris squeezed out. The hair swatches are rolled and secured onto ½ in.diameter roller and dried at 49° C. for approximately an hour. The driedhair is removed from the roller and the resulting curl is suspended bythe bound end. The curl height is measured for each swatch.

Each curl is sprayed uniformly with 4 sprays per side. The curl isplaced in an aluminium pan and placed in a 49° C. oven for about 30minutes to dry. The dried curl is then resuspended, and the curl lengthis measured for time 0 minutes, and set into Thermotron at 22° C., 95%R.H. The curl height is measured after 24 hours.

Curl retention was calculated as follows:

${\%\mspace{14mu}{Curl}\mspace{14mu}{Retention}} = {\frac{L - L^{\prime}}{L - L^{{^\circ}}} \times 100}$

-   -   where        -   L is length of hair fully extended, 6 in.        -   L° is length of curl before spray and exposure, and        -   L′ is length of curl after spray and exposure.

Style retention was evaluated as follows: after 24 hours exposure tohigh humidity, the curl was combed 10 times. The style retention wasjudged based on the curl's ability to retain its initial shape andlength. In most cases, the curl remained unaffected by combing.

Feel was evaluated as follows: untreated hair and hair and treated withPUD were subjected to a panel of 10 judges. Panelists were asked to rankthe feel from 1-5, with 1 being the most natural soft feel with norevealing presence of the polymer.

Adhesion to hair was evaluated by running a comb through the treatedhair, and visually observing the comb and the hair for flakes andresidue.

Ex. 3 Ex. 5 Ex. 6 Ex. 7 Component Ex. 1 Ex. 2 (Comp.) Ex. 4 (Comp.)(Comp.) (Comp.) Desmophen PE 170HN 32.08 31.95 32.22 30.70 32.23 32.2332.24 DMBA 0 0.24 0 0 0 0 0.17 Neopentylglycol 0.19 0 0 0.23 0 0.19 0Desmodur H 5.71 5.69 5.71 5.45 5.74 5.74 5.74 Triethylamine 0 0 0 0 0 00.13 AMP 95 0 0.17 0 0 0 0 0 AAS Na salt 1.7 1.05 1.52 1.62 1.52 1.731.06 Dipropylamine 0.66 1.31 0 0 0 0 0 diethyleneglycol Diethanolamine0.61 0.93 0 0.79 1.07 0.62 1.04 Ethylenediamine 0.16 0 0.33 0.11 0.330.33 0.33 Diethylene Glycol 0 0 0 .25 0 0 0 Water 58.37 58.14 60.2260.36 58.6 58.64 58.77 % Solids 36.5 37.8 40.0 35.0 34.0 34.1 35.0 pH6-8 7.14 6-8 N/A 7.01 N/A N/A Mean particle size, nm 175 146 250 165 255171 285 Viscosity @ 25 C., cps 171 135 300 89 54 57 59 Property Ex. 1Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 % Curl Retention 95 92 97.5 95 96 8583 Style Retention 2 2.5 1 1 1 2 1 Adhesion to Hair 1 1 5 1 2 3 3 Feel 12.5 2 2 2 1 2 Removability 1 1 1 1 1 1 1

As can be seen, Examples 1 and 2, according to the invention, gavesurprisingly good results with regard to adhesion to hair, feel andremovability, while still providing acceptable results with regard tocurl and style retention. In contrast, in the comparative examples,white soft globular residue was observed on hair after drying andcombing. The flakiness was extensive and very notable. The polymer'sresidue was also observed on the comb.

Example 8 Suntan Lotion

A suntan lotion was formulated using the polyurethane dispersion ofExample 1, and having an SPF rating of 30+:

Phase Ingredients Wt. % A-water Propylene Glycol 1.00 D.I. Water 59.75PUD of Example 1 5.00 Polargel UV 1116 (Amcol) 3.75 Methylparaben and1.0 Butylparaben, and Propylparaben B-Oil Octyl methoxycinnamate 5.0Octyl salicylate 3.0 Oxybenzone 3.0 Avobenzone 2.0 Isopropyl Myristate5.0 Stearyl Alcohol 2.0 Glyceryl Stearate 2.0 Stearic acid 2.0Polyethylene 2.5 Cetyl Phosphate 1.0 Total 100.00

Although the invention has been described in detail in the foregoing forthe purpose of illustration, it is to be understood that such detail issolely for that purpose and that variations can be made therein by thoseskilled in the art without departing from the spirit and scope of theinvention except as it may be limited by the claims.

1. An aqueous polyurethane dispersion suitable for use in personal careproducts, the dispersed polyurethane comprising the reaction product of:A) a prepolymer according to the formula:

wherein R₁ represents a bivalent radical of a polyol, R₂ represents aradical of an aliphatic or cycloaliphatic polyisocyanate, R₃ representsa radical of a low molecular weight diol, optionally substituted withionic groups, n is from 0 to 5, and m is >1; B) at least one chainextender according to the formula:H₂N—R₄—NH₂ wherein R₄ represents an alkylene or alkylene oxide radicalnot substituted with ionic or potentially ionic groups; and C) at leastone chain extender selected from the group consisting of the sodium saltof N-(2-aminoethyl)-2-aminoethane sulfonic acid and compounds accordingto the formula:H₂N—R₅—NH₂ wherein R₅ represents an alkylene radical substituted withionic or potentially ionic groups.
 2. The aqueous polyurethanedispersion of claim 1, wherein the reactants further include a chainterminator according to the formula:

wherein R₆ is an H atom or alkylene radical optionally having a hydroxylend and R₇ is alkylene radical optionally having a hydroxyl end.
 3. Theaqueous polyurethane of claim 2, wherein the chain terminator isselected from the group consisting of methylamine, ethylamine,propylamine, butylamine, octylamine, laurylamine, stearylamine,isononyloxy-propylamine, dimethylamine, diethylamine, dipropylamine,dibutylamine, N-methylaminopropylamine, diethyl(methyl)aminopropylamine,morpholine, piperidine and diethanolamine, amide amines of diprimaryamines and monocarboxylic acids, monoketimes of diprimary amines,primary/tertiary amines, methanol, butanol, hexanol, 2-ethylhexylalcohol, isodecyl alcohol, aminomethylpropanol and mixtures thereof. 4.The aqueous polyurethane of claim 1, wherein the polyisocyanate isselected from the group consisting of tetramethylene diisocyanate,1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate,1,4-diisocyanatocyclohexane,3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate (isophoronediisocyanate), 4,4′-diisocyanatodicyclohexylmethane,4,4′-diisocyanatodicyclohexylpropane-(2,2) and mixtures thereof.
 5. Theaqueous polyurethane of claim 1, wherein the low molecular weight diolis selected from the group consisting of ethylene glycol, diethyleneglycol, propane 1,2-diol, propane 1,3-diol, butane 1,4-diol, butylene1,3-glycol, cyclohexane diol, 1,4-cyclohexane dimethanol, hexane1,6-diol, bisphenol A (2,2-bis(4-hydroxyphenyl)propane), hydrogenatedbisphenol A (2,2-bis(4-hydroxycyclohexyl)propane) and mixtures thereof.6. The aqueous polyurethane of claim 1, wherein the first chain extenderB) is a mixture of 3-{2-[2-(3-aminopropoxy)ethoxy]ethoxy}propylamine andethylenediamine.
 7. The aqueous polyurethane of claim 3, wherein thefirst chain extender B) is a mixture of3-{2-[2-(3-aminopropoxy)ethoxy]ethoxy}propylamine and ethylenediamine.8. The aqueous polyurethane of claim 1, wherein the second chainextender C) is the sodium salt of N-(2-aminoethyl)-2-aminoethanesulfonic acid.
 9. The aqueous polyurethane of claim 1, wherein n is from1 to 3, and m is from 1 to
 5. 10. The aqueous polyurethane of claim 1,wherein either R₃ is a radical of diethylene glycol or R₄ is a radicalof 3-{2-[2-(3-aminopropoxy)ethoxy]ethoxy}propylamine.
 11. A hairfixative comprising the aqueous polyurethane dispersion of claim 1 andwater.
 12. A hair fixative comprising the aqueous polyurethanedispersion of claim 1 and ethanol.
 13. A suntan lotion comprising thepolyurethane dispersion of claim 1.